Various N-substituted perfluoroalkanesulfonamides are described in U.S. Pat. No. 3,639,474 as active herbicides and plant growth modifiers. 5-acetamido-2-methyltrifluoromethanesulfonanilide and 5-acetamido-2-chlorotrifluoromethanesulfonanilide are particularly disclosed therein to have plant growth modifying activity, including the ability to retard the growth of grass without significant distortion of the normal foliar shape. (This plant growth modifying activity is of interest because it reduces the number of times grass must be mowed.) U.S. Pat. No. 3,894,078 teaches the compound 5-acetamido-2,4-dimethyl-trifluoromethanesulfonanilide and its use a plant growth regulator. However, no N,N-diacylaminoperfluoroalkanesulfonanilide has been reported.